✨ ベストアンサー ✨
She maybe in her forties.
I'm sorry but my Japanese is not so good.
My or her in both places is used in English.
Japanese does not belong to me but the way I use it is spoken of.
Forty does not belong to her but it is her age. We don't say Her age is forty very often so we take her and put the decade marker after it.
I am in my fifties. I don't tell you exactly how old I am. I just say I am fifty + some years.
日本語で10台という
英語は10台
２０台
30台
それを話すとき
His/her を使う
His twenties
Her thirties
My forties
In ... の thirties. Where ... refers to a person and no makes it belong to the person.
This is just a rule. There is no actual logic to this one.
Sure in this case means there is no worry. The win seems to be guaranteed.